Conventional electronic cameras are known in which the light from an object is converted into electrical signals by an image sensor including a CCD (charge coupled device) and the electrical signals are converted into digital data to be recorded into a recording medium such as a flash memory and the like. Generally, the electronic camera has a color LCD (liquid crystal display) on its rear part. An object to be photographed is displayed on the color LCD as a moving image as follows.
First, the image sensor accumulates the light energy, which is received from an object, as charges. The accumulated charges are read out as electrical signals at a predetermined time interval. On the read-out electrical signals, processing including A/D conversion processing and color processing is performed, and the processed signals are stored into a work memory such as a DRAM as image data.
At the same time, the image data is also output to a displaying section, and an imaging process is performed on the image data by a video encoder. The color LCD generates the image of an object from the image data on which the imaging process has been performed and displays it as a moving image. The color LCD is then used as a viewfinder to determine a photo composition.
The image sensor includes a large number of photoelectric conversion elements and charge transfer electrodes both formed on a semiconductor substrate. As such a type of image sensor, an image sensor is known in which a moving-image photographing mode and a still-image photographing mode can be switched each other.
In the moving-image photographing mode, the blooming (a leakage of charges between adjacent photoelectric conversion elements or from photoelectric conversion elements to charge transfer electrodes) is reduced by adjusting voltage differences within the image sensor.
In the still-image photographing mode, the occurrence of the blooming is not prevented. Therefore, the still-image photographing mode is not generally suited to taking a moving picture.
In conventional electronic cameras, it is required for the release time lag (time required from when a release button is fully pressed until a shutter actually operates) to be shortened as much as possible. This is because, when a moving object is photographed, for example, it is easier for the person who takes a photo to decide a timing of full-pressing the release button as the release time lag is made shorter, which leads to making continuous shooting a snap. Contrarily, longer release time lag may cause difficulty releasing the shutter at the right moment and stress on the person who takes a photo.